Problema Solution
Amber is examining her calling card portion of her phone bill. A 4-minute call at the night rate costs $2.65 and a 10-minute call at the night rate costs $4.75. Write a linear equation in slope-intercept form to model this situation.
Answer provided by our tutors
let 'x' represent the constant portion of the bill and 'r' represent the cost per minute for a night rate call, then:
2.65 = 4r + x
4.75 = 10r + x
solving this system we have:
x = 0.35
r = 1.25
let 'm' represent the number of night minutes, the total bill, 'T', is then modelled by this equation:
T = 0.35m + 1.25